Xiangdong Ye

Coordination compound films of 1-phenyl-5-mercaptotetrazole on copper surface

Abstract The chemical nature of the coordination compound film formed by reacting PMTA (1-phenyl-5-mercaptotetrazole) with a copper surface has been studied by accelerated corrosion tests, linear sweep voltammetry (LSV), cyclic voltammetry (CV), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). These studies show that, in retarding the corrosion of copper substrate, the film is superior to those formed by TTA (tetrazole), BTA (benzotriazole), HBTA (hydroxybenzotriazole), MBT (2-mercaptobenzothiazole), MBI (2-mercaptobenzo-imidazole), 2-AP (2-aminopyrimidine), IBM (imidazole) and chromates. The surface film has been characterized and found to be a polymeric complex of Cu–PMTA. The mechanism for film formation and relationships between this novel film structure and the observed inhibition behavior are discussed.

Effects of exposure time on defects and demolding force in soft ultraviolet nanoimprint lithography

Based on a contact process, the ultraviolet (UV) nanoimprint process can overcome the linewidth limit of conventional photolithography caused by the diffraction effect. However, the contact between the mold and resist may introduce various defects to the two components. Some researchers have investigated the defects that emerge in the imprint process, such as particle contamination and curing shrinkage of the resist. However, the curing process of the resist itself should be studied because the curable resist is the carrier of the pattern transfer and the replication is accomplished by its shape remodeling. In this article, the authors focus on the effects of exposure time on the defects and demolding force in the soft UV imprint process. The replications are made by a soft polydimethylsiloxane mold under the same process parameters except that the curing time is different. Moreover, the curing degree of the resist and the value of the demolding force under various curing doses are measured. A mechanical ...

Room-temperature capillary-imprint lithography for making micro-/nanostructures in large areas

Compared to imprint techniques under the driving condition of external imprint pressure, imprint lithography under capillary force has the advantages of being suitable to produce large feature patterns, simple mold structure, very low imprint pressure, and conformal contact between the mold and the substrate. However, in existing capillary-force lithography, the necessary heating process will bring problems, such as separation between the mold and the substrate, long imprint time, shorter lifetime of the mold, etc. In this article, the authors propose a technique of room-temperature capillary-imprint lithography which is applied to making both micro- and nanostructures simultaneously in large areas under low temperature. In order to prevent the polydimethylsiloxane mold from swelling in the imprint process, a new ultraviolet curable resist is introduced in the imprint process. This resist contains no solvents and has a wide range of viscosity. Through the experiment, three-dimensional microstructures are ...

M-S (M=Mo, W) cluster compound films on copper surfaces

Abstract M-S cluster compound films on copper surfaces were investigated by XPS, AES and FT-IR. The results show that MoSCu and WSCu bonds had been formed by the reaction of MoS42− and WS42−, respectively, with the Cu2O layer on a copper surface. The films are composed of the elements Mo(W), S, Cu and O. The valence of each element is +6, −2, +1 and −2, respectively. According to the AES depth profile curves, the relative atomic contents of the elements were estimated and a multimolecular layer structure of the films was verified. Some of the sulfur atoms had been oxidized in the outer molecular layers while MoS4 or WS2 units remain in the inner molecular layers. The thickness of the film was found to depend on the reaction time: longer times resulted in thicker films. The colors of the films are probably caused by a statistical distribution of various layers since the films are complicated multicomponent and multilayer systems.

Research on the Forming Mechanism of Micro/Nano Features during the Cast Molding Process

Cast molding process has provided a reliable, simple and cost-effective way to fabricate micro structures since decades ago. In order to obtain structures with fine, dense and deep nano-size features by cast molding, it is necessary to study the forming mechanism in the process. In this paper, based on major steps of cast molding, filling models of liquid are established and solved; and the forming mechanism of liquid is revealed. Moreover, the scale effect between the liquid and the cavity on the filling velocity of liquid is studied. It is also interesting to find out that the wettability of liquid on the cavity may be changed from wetting to dewetting depends on the pressure difference. Finally, we experimentally verify some of our modeling results on the flowing and filling state of the liquid during the cast molding process.

Making modified fluoropolymer films with low surface energy

A technique of using commercial polymers and additive to fabricate modified fluoropolymer films with low surface energy is proposed. A small amount of the additive can increase the oleophobic behavior of the fluoropolymer and so reduce its surface energy remarkably. The modified fluoropolymer films not only possess low surface energy and are solvent resistant but also have a high modulus. By a simple cast-molding process, both three-dimensional micropillars and complex letters with 100 nm linewidth can be replicated in the modified fluoropolymer films. Moreover, in the authors’ experiment, the modified fluoropolymer film has shown its replicating competence for replicating high-aspect-ratio sub-30 nm structures.

Making high-fidelity imprint template by resist patterns over a flexible conductive polymer substrate

A technique to fabricate an imprint template is proposed, based on a direct replication of the electronic-beam lithography resist patterns over a flexible conductive polymer substrate. This approach will simplify the template-making process because no anisotropic dry etching is required to transfer the resist pattern into a template material as usual. The flexible polymer film used as the substrate will be helpful during the detaching step of the template obtained; moreover, the flexibility of the substrate can be used to fabricate templates with curved-surface patterns. Using the technique, both the polymer templates and metal templates can be fabricated, and the above advantages will allow the templates to obtain the high-fidelity patterns directly from the electronic-beam lithography.